Dishwashing compositions constitute a generally recognized distinct class of detergent compositions, particularly when compared to detergents designed for fabric washing. For example, the ultimate dishwashing composition results in a spotless and film-free appearance on glassware and silverware after a cleaning cycle in a dishwashing machine. In fabric washing operations, on the otherhand, detergent compositions which result in greasy, oily or soapy residues on items that were cleaned can be tolerated.
Often, washing articles in a commercially available dishwashing machine entails using three products. Salt is added to the salt compartment to recharge the ion exchanger which softens the water, a dishwashing formulation is used to clean the articles and a rinse aid is used to ensure that the articles are rinsed with no streaks or smears. Consumers generally find it very inconvenient, however, to replace or refill such products.
In order to provide convenient products to consumers, manufacturers have been making dishwashing tablets in order to eliminate detergent handling and dosing issues. Such tablets often have a detergent portion, and a wax portion which contains a rinse aid. These types of tablets, which are sometimes referred to as 2-in-1 tablets, have disadvantages since they may only be used in a wash cycle that does not exceed 55.degree. C. This is true because the wax portion which contains the rinse aid will completely dissolve in a wash cycle that exceeds 55.degree. C. This causes all of the rinse aid to drain out of the dishwashing machine before the actual rinse cycle. Furthermore, such 2-in-1 tablets require that salt be added to the dishwashing machine in order to obtain optimal results, and they are very complicated and expensive to produce.
Other types of tablets that are well known are often referred to as pH sensitive 2-in-1 tablets . These types of tablets have a detergent portion and rinse aid portion that is contained in a pH sensitive material. The pH sensitive 2-in-1 tablets may be used in wash cycles that exceed 55.degree. C. However, like the detergent tablets with the wax portion, the pH sensitive 2-in-1 tablets require that salt be added to the dishwashing machine in order to obtain optimal cleaning results and they are extremely expensive to produce.
In view of the vast deficiencies of the conventional products, it is of increasing interest to provide a dishwashing composition, such as a dishwashing tablet, that works well at all wash temperatures of a dishwashing system (even temperatures greater than 55.degree. C.), provides antiscaling benefits in a system that is high in phosphate content (in hard water), does result in excellent cleaning benefits in water that has not been subjected to conventional water softening additives (i.e., hard water) and provides a glossy glassware appearance in the absence of conventional rinse aid compositions. This invention, therefore, is directed to a dishwashing composition that has a polymer comprising a positive charge and a water soluble polymer that reduces phosphate scale formation on glassware being cleaned. The dishwashing composition is superior in that it unexpectedly results in excellent cleaning properties, and reduced spotting and scale formation even when no salt is added to the dishwashing machine to soften hard water, when washing cycles exceed a temperature of 55.degree. C., and when no rinse aid composition is added to the dishwashing machine. In fact, the present invention is directed to a superior 3-in-1 detergent composition that is inexpensive to produce and very easy for the consumer to use.